While zipping down a bike path along the beach in San Diego last August, Bruce J. Tromberg saw a huge pole directly ahead of him. He swerved to the left, but it was too late. He slammed his shoulder into the pole first, and then hit his chest. The injured chemist headed home, to Irvine, where he went to an emergency room. His arm was badly bruised, two of his ribs were broken, . . .